1. Field of the Invention
The invention is directed to a method and to an apparatus for non-contacting information transmission between a data carrier and a data reader, whereby a data generator and the data reader are locationally independent from one another and are brought together for information transmission.
The invention is further directed to an apparatus for non-contacting energy transmission, as well as to an apparatus for non-contacting modification of the electronic memory of the data carrier.
2. Description of the Related Art
German Pat. No. 31 49 789 discloses an apparatus which is referred to therein as inductive identification of an information and is especially suited for the interaction of an electronic key with a lock. Given this apparatus, an oscillator in the lock resonates and the high-frequency oscillation is picked up by the key when it approaches, the oscillation is modulated with a frequency or pulse pattern as key identifier and then the oscillation is retransmitted to the lock and further processed by an electronic recognition means in the lock. The output and return transmission of the high-frequency oscillation is accomplished by coils, i.e. inductively.
Such an inductive transmission is possible in a lock-key system because adequate space for a coil is provided in the key. One disadvantage, however, is that relatively large stray fields are emitted from the coils so that the transmission is therefore very high-loss. In many other data carriers, the accomodation of a coil is either hot possible or requires too great a thickness of the data carrier when they are flat as, for example in credit cards.